Motorized rotary swivel equipped with a dynamometric measuring unit

ABSTRACT

A motorised rotary swivel for driving drill pipe in rotation is disclosed. The swivel includes a measuring unit for measuring a dynamometric behavior of the drill pipe which is mounted adjacent to the output of the motor between the motor and a torque wench assembly.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a rotary swivel equipped with adynamometric measuring unit and, more especially to such a rotary swivelintended to drive a drill pipe in rotation.

2. Description of the Prior Art

There are two types of devices which can be used on a drilling mast fordriving a string of pipe in rotation. The first, and the moretraditional, is the rotary turn-table which is mounted on the floor ofthe drilling mast and comprises a square or hexagonal opening intendedto receive a drive rod of complementary cross-section. The turn-table isset in rotation and thus causes the rotation of the string of pipe

The other type of device is the motorised rotary swivel, where anelectric or hydraulic motor, mounted adjacent to the movable pulleyblock, is linked directly to the upper end of the string of pipe. Themotor is mounted on a carriage which slides on rails arranged verticallyon the mast thus permitting the movement of the carriage whilstabsorbing the torque generated during drilling.

On the other hand, there are dynamometric measuring units which areintended to be mounted on the string of pipe in order to be able tomeasure the forces and sense the various vibrations of the said stringof pipe which are generated during drilling and which can becharacteristic either of the behaviour of the string of pipe, or of thestate of wear of the tool, or even of the type of rock being destroyed.

Patent Application FR 89 08649 which was filed on 28 Jun. 1989 in thename of the applicant describes such a dynamometric measuring unit fordrill pipe in which a series of sensors is mounted on a drill-rodelement of reduced length, more ordinarily called "sub". This device ismounted on the upper end of the string of pipe below the automaticwrench which is arranged at the output of the motor.

Despite these advantages, the positioning of the dynamometric measuringunit below the dynamometric wrench is a source of difficulties because,during certain manoeuvres, for example the withdrawal of only someelements of the string of pipe whilst maintaining the circulation ofmud, it is necessary to withdraw the measuring unit beforehand. Extratime, resulting from this withdrawal and reassembly of the measuringunit, is thus added to the manoeuvre.

SUMMARY OF THE INVENTION

The object of the present invention is to offset these drawbacks byproposing a motorised rotary swivel equipped with a dynamometricmeasuring unit which is of simple construction, reliable and whichallows all types of manoeuvre to be carried out without disassembly ofthe measuring unit.

In order to do this, the invention proposes a motorised rotary swivel,intended to drive a drill pipe in rotation, comprising a motor equippedwith a principal shaft, characterised in that the rotary swivelcomprises, moreover, a measuring unit, comprising at least one sensor,mounted on an extension of the principal shaft adjacent to the output ofthe motor.

Other features and advantages of the present invention will appear moreclearly on reading the description hereinbelow, which is made, by way ofexample, with reference to the appended drawings in which:

BRIEF DESCRIPTION OF THE FIGURES OF DRAWING

FIG. 1 is a view in perspective of a motorised rotary swivel equippedwith a dynamometric measuring unit according to the present invention,

FIG. 2 is a view in perspective of a measuring unit intended to bemounted in the rotary swivel of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIG. 1 is shown a motorised rotary swivel 10 securely mounted on acarriage 12 equipped with rollers 14 which permit the said carriage toslide on two rails 16 which are arranged vertically and are solidlyconnected to the drilling mast (not shown). The rotary swivel 10comprises a motor 18 which can be electric or hydraulic and whichcomprises a hollow principal shaft 20 which is linked by a bearing to arotary swivel 22 which is also securely mounted on the carriage 12. In atraditional manner, the rotary swivel is suspended from the hook 24 ofthe movable pulley block 26 which forms part of the winch of the mast(not shown).

The rotary swivel 22 is supplied with mud, in a known fashion, by aflexible tube 28 linked to a source of mud under pressure (not shown).Below the motor 18, and linked to the latter by torque transmission arms30, can be found the automatic wrench assembly 32 and 34 of the elevator36.

According to the invention, the dynamometric measuring unit 38 isarranged between the motor 18 and the automatic wrench assembly 32 andthe elevator 36.

As shown in FIG. 2, the dynamometric measuring unit, represented by 38,comprises a hollow shaft 40 which can be either an extension of theprincipal shaft 20 or, in a preferred embodiment, a subassembly intendedto be mounted on the principal shaft 20 by a threaded part (not shown)and arranged adjacent to the output of the motor 18. The hollow shaft 40comprises, at its lower end, a threaded male part 42 intended tointeract with a corresponding female threaded part at the upper end ofthe string of pipe (not shown).

The dynamometric measuring unit 38 comprises a series of sensors solidlymounted on its outer surface and forming a measuring unit. In theexample illustrated, the unit comprises two traction gauges 44 and 46, apair of torsion gauges 48, 50, a temperature gauge 52, a pair oflongitudinal accelerometers 54, 56 and three transverse accelerometers58, 60, 62. Moreover, the unit is equipped with a pressure sensor 64.The data generated by the sensors are processed by an electronicconditioning circuit 66 which permits a digital multiplexing of thesignals. The electronic circuit is linked to a pair of annular tracks68, 70 arranged around the shaft 40. A brush-holder assembly 72, mountedso as to rotate with respect to the shaft 40, is intended to pick up thesignals from the annular tracks 68, 70. This assembly 72 is linked to aconnector 74 arranged on a flange 76 which is also mounted so as torotate freely on the shaft 40, these elements together forming arotating collector assembly. The signals are sent to a processing centreremote from the drilling mast via an ordinary transmission cable 78. Inan alternative embodiment, the signals can be sent by radio or bymagnetic induction. A sheath 80 is intended to be mounted over theflange 76 to protect the various sensors.

Thus, by virtue of the present invention, a centralised measuring unitis arranged in an integral manner in the motorised rotary swivel in sucha way as not to necessitate any extra manoeuvre by the driller.

We claim:
 1. Motorised rotary swivel for driving drill pipe in rotation,comprising a motor equipped with a principal shaft, a torque wrenchassembly, an elevator and a measuring unit for measuring a dynamometricbehavior of the drill pipe, said measuring unit comprising at least onesensor, mounted on the principal shaft or an extension of the principalshaft wherein the measuring unit is mounted adjacent to the output ofthe motor between the motor and the torque wrench assembly.
 2. Motorisedrotary swivel according to claim 1 wherein the measuring unit isarranged on a subassembly designed to be mounted on the principal shaftat the output of the motor.
 3. Motorised rotary swivel according toclaim 1 wherein the measuring unit is linked to a processing centre by acable, the cable being linked to sensors by a rotating collectorassembly.
 4. Motorised rotary swivel according to claim 1 wherein themeasuring unit is linked to a processing centre by radio or by magneticinduction.
 5. Motorised rotary swivel according to claim 1 wherein themeasuring unit comprises a torsion gauge, a traction gauge andaccelerometers.